(Noob questions)Using a USB midi controller with 201

Hi, I’ve read some of the posts on midi in via USB but am unsure what does and doesn’t actually make it work. I am trying to use the class compliant, bus powered arturia minilab 3 to control it,.it does not work after re-entering the mother patch but a friend’s Casio piano worked fine. Any thoughts as to what I could do here or just just general insights on the USB midi implementation? Cheers!